| /** | |
| * \file chachapoly.h | |
| * | |
| * \brief This file contains the AEAD-ChaCha20-Poly1305 definitions and | |
| * functions. | |
| * | |
| * ChaCha20-Poly1305 is an algorithm for Authenticated Encryption | |
| * with Associated Data (AEAD) that can be used to encrypt and | |
| * authenticate data. It is based on ChaCha20 and Poly1305 by Daniel | |
| * Bernstein and was standardized in RFC 7539. | |
| * | |
| * \author Daniel King <damaki.gh@gmail.com> | |
| */ | |
| /* Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved. | |
| * SPDX-License-Identifier: Apache-2.0 | |
| * | |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may | |
| * not use this file except in compliance with the License. | |
| * You may obtain a copy of the License at | |
| * | |
| * http://www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| * | |
| * This file is part of Mbed TLS (https://tls.mbed.org) | |
| */ | |
| #ifndef MBEDTLS_CHACHAPOLY_H | |
| #define MBEDTLS_CHACHAPOLY_H | |
| #if !defined(MBEDTLS_CONFIG_FILE) | |
| #include "config.h" | |
| #else | |
| #include MBEDTLS_CONFIG_FILE | |
| #endif | |
| /* for shared error codes */ | |
| #include "poly1305.h" | |
| #define MBEDTLS_ERR_CHACHAPOLY_BAD_STATE -0x0054 /**< The requested operation is not permitted in the current state. */ | |
| #define MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED -0x0056 /**< Authenticated decryption failed: data was not authentic. */ | |
| #ifdef __cplusplus | |
| extern "C" { | |
| #endif | |
| typedef enum | |
| { | |
| MBEDTLS_CHACHAPOLY_ENCRYPT, /**< The mode value for performing encryption. */ | |
| MBEDTLS_CHACHAPOLY_DECRYPT /**< The mode value for performing decryption. */ | |
| } | |
| mbedtls_chachapoly_mode_t; | |
| #if !defined(MBEDTLS_CHACHAPOLY_ALT) | |
| #include "chacha20.h" | |
| typedef struct mbedtls_chachapoly_context | |
| { | |
| mbedtls_chacha20_context chacha20_ctx; /**< The ChaCha20 context. */ | |
| mbedtls_poly1305_context poly1305_ctx; /**< The Poly1305 context. */ | |
| uint64_t aad_len; /**< The length (bytes) of the Additional Authenticated Data. */ | |
| uint64_t ciphertext_len; /**< The length (bytes) of the ciphertext. */ | |
| int state; /**< The current state of the context. */ | |
| mbedtls_chachapoly_mode_t mode; /**< Cipher mode (encrypt or decrypt). */ | |
| } | |
| mbedtls_chachapoly_context; | |
| #else /* !MBEDTLS_CHACHAPOLY_ALT */ | |
| #include "chachapoly_alt.h" | |
| #endif /* !MBEDTLS_CHACHAPOLY_ALT */ | |
| /** | |
| * \brief This function initializes the specified ChaCha20-Poly1305 context. | |
| * | |
| * It must be the first API called before using | |
| * the context. It must be followed by a call to | |
| * \c mbedtls_chachapoly_setkey() before any operation can be | |
| * done, and to \c mbedtls_chachapoly_free() once all | |
| * operations with that context have been finished. | |
| * | |
| * In order to encrypt or decrypt full messages at once, for | |
| * each message you should make a single call to | |
| * \c mbedtls_chachapoly_crypt_and_tag() or | |
| * \c mbedtls_chachapoly_auth_decrypt(). | |
| * | |
| * In order to encrypt messages piecewise, for each | |
| * message you should make a call to | |
| * \c mbedtls_chachapoly_starts(), then 0 or more calls to | |
| * \c mbedtls_chachapoly_update_aad(), then 0 or more calls to | |
| * \c mbedtls_chachapoly_update(), then one call to | |
| * \c mbedtls_chachapoly_finish(). | |
| * | |
| * \warning Decryption with the piecewise API is discouraged! Always | |
| * use \c mbedtls_chachapoly_auth_decrypt() when possible! | |
| * | |
| * If however this is not possible because the data is too | |
| * large to fit in memory, you need to: | |
| * | |
| * - call \c mbedtls_chachapoly_starts() and (if needed) | |
| * \c mbedtls_chachapoly_update_aad() as above, | |
| * - call \c mbedtls_chachapoly_update() multiple times and | |
| * ensure its output (the plaintext) is NOT used in any other | |
| * way than placing it in temporary storage at this point, | |
| * - call \c mbedtls_chachapoly_finish() to compute the | |
| * authentication tag and compared it in constant time to the | |
| * tag received with the ciphertext. | |
| * | |
| * If the tags are not equal, you must immediately discard | |
| * all previous outputs of \c mbedtls_chachapoly_update(), | |
| * otherwise you can now safely use the plaintext. | |
| * | |
| * \param ctx The ChachaPoly context to initialize. Must not be \c NULL. | |
| */ | |
| void mbedtls_chachapoly_init( mbedtls_chachapoly_context *ctx ); | |
| /** | |
| * \brief This function releases and clears the specified | |
| * ChaCha20-Poly1305 context. | |
| * | |
| * \param ctx The ChachaPoly context to clear. This may be \c NULL, in which | |
| * case this function is a no-op. | |
| */ | |
| void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx ); | |
| /** | |
| * \brief This function sets the ChaCha20-Poly1305 | |
| * symmetric encryption key. | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context to which the key should be | |
| * bound. This must be initialized. | |
| * \param key The \c 256 Bit (\c 32 Bytes) key. | |
| * | |
| * \return \c 0 on success. | |
| * \return A negative error code on failure. | |
| */ | |
| int mbedtls_chachapoly_setkey( mbedtls_chachapoly_context *ctx, | |
| const unsigned char key[32] ); | |
| /** | |
| * \brief This function starts a ChaCha20-Poly1305 encryption or | |
| * decryption operation. | |
| * | |
| * \warning You must never use the same nonce twice with the same key. | |
| * This would void any confidentiality and authenticity | |
| * guarantees for the messages encrypted with the same nonce | |
| * and key. | |
| * | |
| * \note If the context is being used for AAD only (no data to | |
| * encrypt or decrypt) then \p mode can be set to any value. | |
| * | |
| * \warning Decryption with the piecewise API is discouraged, see the | |
| * warning on \c mbedtls_chachapoly_init(). | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context. This must be initialized | |
| * and bound to a key. | |
| * \param nonce The nonce/IV to use for the message. | |
| * This must be a redable buffer of length \c 12 Bytes. | |
| * \param mode The operation to perform: #MBEDTLS_CHACHAPOLY_ENCRYPT or | |
| * #MBEDTLS_CHACHAPOLY_DECRYPT (discouraged, see warning). | |
| * | |
| * \return \c 0 on success. | |
| * \return A negative error code on failure. | |
| */ | |
| int mbedtls_chachapoly_starts( mbedtls_chachapoly_context *ctx, | |
| const unsigned char nonce[12], | |
| mbedtls_chachapoly_mode_t mode ); | |
| /** | |
| * \brief This function feeds additional data to be authenticated | |
| * into an ongoing ChaCha20-Poly1305 operation. | |
| * | |
| * The Additional Authenticated Data (AAD), also called | |
| * Associated Data (AD) is only authenticated but not | |
| * encrypted nor included in the encrypted output. It is | |
| * usually transmitted separately from the ciphertext or | |
| * computed locally by each party. | |
| * | |
| * \note This function is called before data is encrypted/decrypted. | |
| * I.e. call this function to process the AAD before calling | |
| * \c mbedtls_chachapoly_update(). | |
| * | |
| * You may call this function multiple times to process | |
| * an arbitrary amount of AAD. It is permitted to call | |
| * this function 0 times, if no AAD is used. | |
| * | |
| * This function cannot be called any more if data has | |
| * been processed by \c mbedtls_chachapoly_update(), | |
| * or if the context has been finished. | |
| * | |
| * \warning Decryption with the piecewise API is discouraged, see the | |
| * warning on \c mbedtls_chachapoly_init(). | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context. This must be initialized | |
| * and bound to a key. | |
| * \param aad_len The length in Bytes of the AAD. The length has no | |
| * restrictions. | |
| * \param aad Buffer containing the AAD. | |
| * This pointer can be \c NULL if `aad_len == 0`. | |
| * | |
| * \return \c 0 on success. | |
| * \return #MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA | |
| * if \p ctx or \p aad are NULL. | |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE | |
| * if the operations has not been started or has been | |
| * finished, or if the AAD has been finished. | |
| */ | |
| int mbedtls_chachapoly_update_aad( mbedtls_chachapoly_context *ctx, | |
| const unsigned char *aad, | |
| size_t aad_len ); | |
| /** | |
| * \brief Thus function feeds data to be encrypted or decrypted | |
| * into an on-going ChaCha20-Poly1305 | |
| * operation. | |
| * | |
| * The direction (encryption or decryption) depends on the | |
| * mode that was given when calling | |
| * \c mbedtls_chachapoly_starts(). | |
| * | |
| * You may call this function multiple times to process | |
| * an arbitrary amount of data. It is permitted to call | |
| * this function 0 times, if no data is to be encrypted | |
| * or decrypted. | |
| * | |
| * \warning Decryption with the piecewise API is discouraged, see the | |
| * warning on \c mbedtls_chachapoly_init(). | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. | |
| * \param len The length (in bytes) of the data to encrypt or decrypt. | |
| * \param input The buffer containing the data to encrypt or decrypt. | |
| * This pointer can be \c NULL if `len == 0`. | |
| * \param output The buffer to where the encrypted or decrypted data is | |
| * written. This must be able to hold \p len bytes. | |
| * This pointer can be \c NULL if `len == 0`. | |
| * | |
| * \return \c 0 on success. | |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE | |
| * if the operation has not been started or has been | |
| * finished. | |
| * \return Another negative error code on other kinds of failure. | |
| */ | |
| int mbedtls_chachapoly_update( mbedtls_chachapoly_context *ctx, | |
| size_t len, | |
| const unsigned char *input, | |
| unsigned char *output ); | |
| /** | |
| * \brief This function finished the ChaCha20-Poly1305 operation and | |
| * generates the MAC (authentication tag). | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. | |
| * \param mac The buffer to where the 128-bit (16 bytes) MAC is written. | |
| * | |
| * \warning Decryption with the piecewise API is discouraged, see the | |
| * warning on \c mbedtls_chachapoly_init(). | |
| * | |
| * \return \c 0 on success. | |
| * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE | |
| * if the operation has not been started or has been | |
| * finished. | |
| * \return Another negative error code on other kinds of failure. | |
| */ | |
| int mbedtls_chachapoly_finish( mbedtls_chachapoly_context *ctx, | |
| unsigned char mac[16] ); | |
| /** | |
| * \brief This function performs a complete ChaCha20-Poly1305 | |
| * authenticated encryption with the previously-set key. | |
| * | |
| * \note Before using this function, you must set the key with | |
| * \c mbedtls_chachapoly_setkey(). | |
| * | |
| * \warning You must never use the same nonce twice with the same key. | |
| * This would void any confidentiality and authenticity | |
| * guarantees for the messages encrypted with the same nonce | |
| * and key. | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context to use (holds the key). | |
| * This must be initialized. | |
| * \param length The length (in bytes) of the data to encrypt or decrypt. | |
| * \param nonce The 96-bit (12 bytes) nonce/IV to use. | |
| * \param aad The buffer containing the additional authenticated | |
| * data (AAD). This pointer can be \c NULL if `aad_len == 0`. | |
| * \param aad_len The length (in bytes) of the AAD data to process. | |
| * \param input The buffer containing the data to encrypt or decrypt. | |
| * This pointer can be \c NULL if `ilen == 0`. | |
| * \param output The buffer to where the encrypted or decrypted data | |
| * is written. This pointer can be \c NULL if `ilen == 0`. | |
| * \param tag The buffer to where the computed 128-bit (16 bytes) MAC | |
| * is written. This must not be \c NULL. | |
| * | |
| * \return \c 0 on success. | |
| * \return A negative error code on failure. | |
| */ | |
| int mbedtls_chachapoly_encrypt_and_tag( mbedtls_chachapoly_context *ctx, | |
| size_t length, | |
| const unsigned char nonce[12], | |
| const unsigned char *aad, | |
| size_t aad_len, | |
| const unsigned char *input, | |
| unsigned char *output, | |
| unsigned char tag[16] ); | |
| /** | |
| * \brief This function performs a complete ChaCha20-Poly1305 | |
| * authenticated decryption with the previously-set key. | |
| * | |
| * \note Before using this function, you must set the key with | |
| * \c mbedtls_chachapoly_setkey(). | |
| * | |
| * \param ctx The ChaCha20-Poly1305 context to use (holds the key). | |
| * \param length The length (in Bytes) of the data to decrypt. | |
| * \param nonce The \c 96 Bit (\c 12 bytes) nonce/IV to use. | |
| * \param aad The buffer containing the additional authenticated data (AAD). | |
| * This pointer can be \c NULL if `aad_len == 0`. | |
| * \param aad_len The length (in bytes) of the AAD data to process. | |
| * \param tag The buffer holding the authentication tag. | |
| * This must be a readable buffer of length \c 16 Bytes. | |
| * \param input The buffer containing the data to decrypt. | |
| * This pointer can be \c NULL if `ilen == 0`. | |
| * \param output The buffer to where the decrypted data is written. | |
| * This pointer can be \c NULL if `ilen == 0`. | |
| * | |
| * \return \c 0 on success. | |
| * \return #MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED | |
| * if the data was not authentic. | |
| * \return Another negative error code on other kinds of failure. | |
| */ | |
| int mbedtls_chachapoly_auth_decrypt( mbedtls_chachapoly_context *ctx, | |
| size_t length, | |
| const unsigned char nonce[12], | |
| const unsigned char *aad, | |
| size_t aad_len, | |
| const unsigned char tag[16], | |
| const unsigned char *input, | |
| unsigned char *output ); | |
| #if defined(MBEDTLS_SELF_TEST) | |
| /** | |
| * \brief The ChaCha20-Poly1305 checkup routine. | |
| * | |
| * \return \c 0 on success. | |
| * \return \c 1 on failure. | |
| */ | |
| int mbedtls_chachapoly_self_test( int verbose ); | |
| #endif /* MBEDTLS_SELF_TEST */ | |
| #ifdef __cplusplus | |
| } | |
| #endif | |
| #endif /* MBEDTLS_CHACHAPOLY_H */ |